A reverse-conducting insulated-gate bipolar transistor (RC-IGBT) is a type of bipolar-type transistor. The RC-IGBT is a high-voltage power element, but has an issue in that on-resistance is high. Thus, reduction in loss due to this has been implemented by, for example, connecting a low-loss MOSFET using a wide-gap semiconductor such as SiC in parallel to the RC-IGBT and simultaneously turning on the RC-IGBT and the MOSFET. Hereafter, the operation in which the IGBT and the FET are simultaneously turned on may be referred to as “direct-current (DC) assist.”